The present invention is related to a method of depositing a zinc oxide coating on a transparent substrate; more particularly, it is related to a chemical vapor deposition method of depositing a zinc oxide coating on a glass substrate.
Deposition of metal oxide coatings reacted with H2O has been reported in the patent literature. For example:
U.S. Pat. No. 4,751,149 describes a chemical vapor deposition (CVD) process for depositing zinc oxide films having certain properties which make them useful in photoconductive applications, such as in solar cells, and other photovoltaic devices. The deposition process includes introducing an organozinc compound, an oxidant and an inert carrier gas into a chamber containing a substrate heated to a temperature in the range of about 60° C. to 350° C. The resulting zinc oxide films are said to have a resistivity in the range of about 10−4 to 10−2 ohm centimeter. Such films contain hydrogen and may be fabricated to contain a Group III element by introducing volatile Group III compounds into the chamber along with the organozinc compound and oxidant.
U.S. Pat. No. 5,698,262 describes a method for making doped tin oxide coatings utilizing a uniform, vaporized reactant mixture containing an organotin compound, hydrofluoric acid, water and oxygen, and delivering the reactant mixture to a surface of a hot ribbon of glass, where the above-mentioned compounds react to form the fluorine doped tin oxide coating. The fluorine doped tin oxide coatings deposited in accordance with the invention exhibit lower sheet resistance and improved uniformity in sheet resistance over the coated surface of the glass substrate.
It would be desirable to be able to make zinc oxide films at high deposition rates by atmospheric pressure chemical vapor deposition during the float glass manufacturing process, utilizing relatively inexpensive precursor materials.